More specifically, the FSK facing sheet material laminate of the subject invention relates to a FSK facing sheet material laminate that offers opportunities for increased productivity and manufacturing cost reductions and that: exhibits enhanced dimensional stability and reduced deformation and wrinkling (“dimpling”); mold and mildew growth resistance; stain resistance; improved tape adhesion, improved ease of cleaning, enhanced flame spread resistance; good handleability; UV resistance; surface abrasion resistance; and overall good surface aesthetics prior to and during service. The FSK facing sheet material laminates of the subject invention may include one or more humectant(s); one or more water, oil, and/or grease repellant components; and/or a paper composite sheet of the paper composite sheet layer that includes synthetic and/or inorganic fibers so that when the facing sheet material is exposed to conditions of high heat and humidity (e.g. temperatures equal to or greater than 75° F. and relative humidities equal to or greater than 50%), the paper composite sheet layer of the FSK facing sheet material laminate exhibits enhanced dimensional stability and reduced deformation and wrinkling (“dimpling”). Preferably, the FSK facing sheet material laminate of the subject invention includes one or more flame retardants, fungi growth inhibiting agents, and/or other additives to enhance the performance of the laminate and the adhesive of the FSK facing sheet material laminate includes synthetic fibers and/or inorganic fibers to further enhance the dimensional stability and stiffness of the paper composite sheet layer and further reduce deformation and wrinkling (“dimpling”) of the paper composite sheet layer when the FSK facing sheet material laminate of the subject invention is exposed to conditions of high heat and humidity. It is also contemplated that the paper composite sheet of the paper composite sheet layer may contain only synthetic and/or inorganic fibers and no cellulose fibers for dimensional stability and stiffness and reduced deformation and wrinkling (“dimpling”) of the paper composite sheet layer when the FSK facing sheet material laminate of the subject invention is exposed to conditions of high heat and humidity. The faced insulation products of the subject invention that are faced with the FSK facing sheet material laminate of the subject invention include pipe insulation, duct board, duct wrap insulation, metal building insulation, and other building insulation products.
Current commercially available FSK facing sheet material laminates have an aluminum foil or metallized polyester film sheet forming an inner layer of the laminate, a kraft paper sheet forming an outer exposed layer of the laminate, a scrim intermediate the foil or metallized polyester film sheet layer and the paper sheet layer, and an adhesive that bonds the foil or metallized polyester film sheet layer, the scrim layer, and the paper sheet layer together. In use, the aluminum foil or metallized polyester film sheet forming the inner layer of these FSK facing sheet material laminates is bonded directly to a surface of an insulation product and the kraft paper sheet forming the outer layer of these FSK facing sheet material laminates becomes the visible surface of the faced insulation product. When these FSK facing sheet material laminates are exposed to conditions of high heat and humidity, the foil or metallized polyester film layer of these FSK facing sheet material laminates remains dimensionally stable while the kraft paper sheet layer of these FSK facing sheet material laminates absorbs moisture and expands. Furthermore, the aluminum foil or metallized polyester film layer of these FSK facing sheet material laminates is typically stiffer or more rigid than the kraft paper sheet layer of the laminates. Since the dimensionally stable, more rigid, foil or metallized polyester film layer and the kraft paper sheet layer of these FSK facing sheet material laminates are bonded together, the expansion of the kraft paper sheet layer relative to the dimensionally stable foil or metallized polyester film layer under conditions of high heat and humidity causes the kraft paper sheet layer to deform and wrinkle. This deformation and wrinkling of the kraft paper sheet layer adversely affects the visible surface of a faced insulation product by changing the visible surface from a smooth visibly pleasing surface to a surface having a visually unappealing mottled finish that can resemble the dimples on a golf ball. This visually unappealing mottled finish is commonly called “dimpling” in the industry.
Since the faced surfaces of many FSK faced insulation products remain exposed and many FSK faced insulation products, especially pipe insulation products, are frequently exposed to numerous cycles of high heat and humidity, there has been a need to provide a FSK facing sheet material laminate with an exposed paper or paper composite sheet layer that is more dimensionally stable and, preferably, stiffer or more rigid than the kraft paper sheet layers of current FSK facing sheet material laminates. In addition, for many applications, there has been a need to provide a FSK facing sheet material laminate that is more flame spread resistant and exhibits other desirable characteristics.